Cornelius Castoriadis was one of the most important and groundbreaking thinkers of the second half of the twentieth century. A philosopher of the radical imaginary, co-founder of the legendary magazine "Socialisme ou Barbarie" (Socialism or Barbarism), a psychoanalyst who renewed Freudian theory, a political thinker of stature who inspired workers and students during the events of May 1968 in France, a prominent economist of the OECD, a recognized Hellenist, an exponent of a libertarian Left, and an advocate of the project of autonomy. Nevertheless, Cornelius Castoriadis does not fit into any of the philosophical currents of the twentieth century. This book is the first complete and systematic monograph in Greece on the entirety of Cornelius Castoriadis's work. At the same time, it can be used as a manual, where each chapter functions independently but also integrates organically into the whole, composing a fascinating mosaic of the philosopher's thought. It fully responds to the Castoriadian position: "One does not honor a thinker by praising or interpreting his work, but by discussing it, thus keeping it alive and practically demonstrating that it defies time and retains its value."